Wikipedia:Reference desk/Archives/Mathematics/2015 December 29

= December 29 =

Intuitive explanation of Binomial coefficients
Could anyone tell why there are only three choices available to pick one y from a set of four boxes containing x and y as given in binomials(P.2).I think it's basically four.JUSTIN JOHNS (talk) 09:14, 29 December 2015 (UTC)


 * I think it's just an error in the pdf.   D b f i r s   10:30, 29 December 2015 (UTC)


 * There is no error. Page 2 talks first about the expansion of (x+y)3, then about the expansion of (x+y)4.  It is talking about x+y)3, when it refers to "the number of ways we can pick one y from a set of 3 boxes"&mdash;not from 4 boxes. The number of ways to pick one y from a set of 4 boxes is not even mentioned on the page. --76.69.45.64 (talk) 05:27, 30 December 2015 (UTC)
 * Sorry! I should have read it more carefully.   D b f i r s   21:16, 30 December 2015 (UTC)

You're right about four boxes but why it says "only three choices are available" in the mentioned pdf.JUSTIN JOHNS (talk) 06:27, 31 December 2015 (UTC)


 * In the final paragraph of the Binomial Expansion section the linked PDF says "In case of  (x + y)4 we have four boxes. The coefficient by x3y means the number of choices to pick one y from four boxes. There are three choices to do so." As was said above, this seems to be an error in the PDF. The coefficient of x3y in the expansion of  (x + y)4 is 4 and there are indeed 4 ways to choose one box from four. Gandalf61 (talk) 07:30, 31 December 2015 (UTC)

Okay thanks for helping me to recognize the error in pdf.JUSTIN JOHNS (talk) 08:18, 31 December 2015 (UTC)


 * Dang. Sorry for missing that and being misleading. --76.69.45.64 (talk) 07:18, 1 January 2016 (UTC)